Waveguide circulators with E-plane transitions have a wide variety of uses in commercial, military, space, terrestrial, low power applications, and high power applications. Such waveguide circulators are important in space applications (for example, in satellites) where reliability is essential and where reducing size and weight is important. Moving parts wear down over time and have a negative impact on long term reliability. Waveguide circulators made from a ferrite material have high reliability due to their lack of moving parts. Thus, the highly reliable ferrite circulators are desirable for space applications.
Rectangular waveguide E-plane layer transitions are often utilized in complex switch matrices. Such complex switch matrices with layer transitions are used on commercial, military, and space products including switched beam antennas, order-constrained beam switching networks, and low noise amplifier (LNA) redundancy switch assemblies.
Order-constrained switch networks require a large number of crossovers between independent paths, and thus require a large number of E-plane layer transitions to implement the path crossovers. The advantages of order-constrained switch networks are discussed in “Technical Report 639—Design of Microwave Beam-Switching Networks,” M. L. Burrows, 5 Dec. 1983, Lincoln Laboratory. Since order-constrained switch networks require a large number of E-plane transitions, and the current technology for E-plane transitions requires a spacing of one-quarter to one-wavelength between the E-plane transition and the ferrite switches, the order-constrained switch networks may become large in size and high in loss.